Clogging refers to a reduction of riverbed hydraulic conductivity. Due to difficulties in determining the thickness of the clogging layer, the leakage coefficient (L) is introduced and used to quantify the recoverable portion of bank filtrate. L was determined at several riverbank filtration (RBF) sites in field tests and using an analytical solution. Results were compared with data from similar experiments in the early 1970s and 1991–1993. In the 1980s, severe river water pollution in conjunction with high water abstraction led to partly unsaturated conditions beneath the riverbed. A leakage coefficient L of 5 × 10 ?7 s ?1 was determined. After water quality improvement, L increased to 1–1.5 × 10 ?6 s ?1 . An alternative, cost and time efficient method is presented to estimate accurate leakage coefficients. The analytical solution is based on groundwater level monitoring data from observation wells next to the river, which can later feed into numerical models. The analytical approach was able to reflect long-term changes as well as seasonal variations. Recommendations for its application are given based on experience.
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机译：堵塞是指河床水力传导率的降低。由于难以确定堵塞层的厚度，因此引入泄漏系数（L）并用于量化堤滤液的可回收部分。 L是在田间测试中使用分析溶液在几个河岸过滤（RBF）站点确定的。将结果与1970年代初和1991–1993年的类似实验数据进行了比较。在1980年代，严重的河水污染和高取水量导致河床下面的部分不饱和条件。测得的漏泄系数L为5×10 7 s -1。水质改善后，L增加到1–1.5×10？6 s？1。提出了另一种节省成本和时间的有效方法来估计准确的泄漏系数。该分析解决方案基于河流旁观察井的地下水位监测数据，这些数据随后可用于数值模型。分析方法能够反映长期变化以及季节性变化。根据经验给出有关其应用的建议。
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